Attention has focused on a number of problems, including reinforcement, sympatric speciation, and the ecological context of speciation.

The concept of sympatric speciation by host-race formation remains contentious because of the restrictive conditions that many workers have suggested are required, based on models using assumptions that may not be true.

Indeed, sympatric speciation events have been observed in controlled experiments, under natural conditions, and also demonstrated by simulation models.

Derivatives

sympatry

In addition, their definition of ‘superspecies’ makes exceptions for narrow sympatry, which obliterates the definition, because ‘allospecies’ should form the components of a superspecies.

Although the two species were not found in sympatry, a population of P. elegans was found only 9 km away from a P. actinia population in Santo Antonio da Patrulha county.

As revealed by comparisons of molecular and morphologic data in modern species, non-hybrid populations form distinct morphologic clusters in sympatry, which do not overlap and are usually separated by gaps.